Mega Math Workshop: Perceptions of Dual-Class Cooperative Learning Stations

This study investigated student and teacher perceptions of Mega Math Workshop, a model combining learning stations, small-group intervention, cooperative learning, and content repetition, as well as its effect on academic achievement. The researcher used surveys, student work samples, interviews, and observational notes to compile data. The qualitative data was analyzed using the constant comparative method, and the quantitative data was analyzed according to measures of central tendency. This data showed a large range in student perspectives on Mega Math Workshop, both negative and positive. Generally, students had a positive opinion of Mega Math Workshop, and their achievement was not adversely affected. The classroom teacher, however, had a more neutral opinion, seeing the opportunities for growth and change

\u3ci\u3eJustice in Young Adult Speculative Fiction: A Cognitive Reading\u3c/i\u3e by Marek Oziewicz

Presented is a review of Justice in Young Adult Speculative Fiction: A Cognitive Reading by Marek C. Oziewicz

Vicarious and Source Credibility: A Cross Cultural Explanation

Two factors represent orientations of credibility elements, vicarious and source credibility. Both orientations include credibility elements: competence, trustworthiness, and goodwill/care. The two factor solution (vicarious = x axis; source = y axis) develops a credibility grid based on five classifications of credibility evaluations. The five credibility grid evaluations are defined by cross-cultural communication theory. Quantitative evidence is derived from three tests (a) the model, (b) the function, and (c) classification. Data from questionnaries involving 1,149 participants are analyzed both within and across US, Spanish, and Japanese cultures. Reliabitliy estimates for US (.75) and Spanish (.63) are stable, but deficient for Japanese (.50) data. A paired-sample t-test both within and across cutlures identify vicarious and source credibility as significantly different, and factor analysis indicates the model is stable. Means and correlation analysis indicate that each of the cultures vary in function related to theory. Classification results from discriminant analysis, where vicarious and source become a single function, identify new grounds for cross-cutlural communication research. Overall results provide new grounds for credibility research by including vicarious credibility as an advancement to source credibility

Proton transfer reactions in photosynthetic water oxidation: Second sphere ligands of the manganese cluster modulate the water oxidation mechanism of Photosystem II

Scope and Method of Study: Physiological and Biophysical characterization of point mutations in the D1 subunit of PSII.Findings and Conclusions: In the D1-D61N mutant, it was possible to resolve a clear lag phase prior to the appearance of O2, indicating formation of an intermediate before onset of O2 formation. The lag phase and the photochemical miss factor were more sensitive to isotope substitution in the mutant indicating that proton efflux in the mutant proceeds via an alternative pathway. The results are discussed in comparison with earlier results obtained from the substitution of CP43-Arg357 with lysine and in regards to hypotheses concerning the nature of the final steps in photosynthetic water oxidation. These considerations lead to the conclusion that proton expulsion during the initial phase of the S3-S0 transition starts with the deprotonation of primary catalytic base, probably CP43-Arg357, followed by efficient proton egress involving the carboxyl group of D1-D61 in a process that constitutes the lag phase immediately prior to O2 formation chemistry. The asparagine, phenylalanine and threonine substitutions to D1-V185 were able to accumulate significant levels of charge separating PSII. Of the three substitutions the phenylalanine substitution was the most severe with a complete inability to evolve oxygen, despite being able to accumulate Photosystem II and to undergo stable charge separations. The threonine substitution had no apparent effect on oxygen evolution other than a 40% reduction in the steady state rate of O2 production compared to type Synechocystis, which can be attributed to that mutants reduced ability to accumulate PSII. The asparagine substitution produced the most complex phenotype. While still able to evolve oxygen, it does so less efficiently than wild type PSII, with a miss factor 4% higher than wild type Synechocystis. The substitution on D1-Val185 with asparagine also decreased the t1/2 of O2 release from thylakoid membranes from 1.2 ms to 10.0 ms and decreased the t1/2 lag phase prior to the onset of O2 release to 2.8 ms. The combination of a long lag period and a decreased rate of O2 release can also be observed in the D1-D61N mutant strains of Synechocystis and in PSII centers in which chloride has been replaced by iodide

Cyclization of S-alkenyl-substituted Phosphonium Salts Using 115% Polyphosphoric Acid-a New Route to Carbon-phosphorus Heterocycles

Chemistr